package com.cody.date160119;

/**
 * 测试String类的immutable特性
 * Created by cody on 16/1/19.
 */
public class Exercise1 {

    public static void main(String[] args) {
        String str = "Hello World!";
        System.out.println(str);
        System.out.println(str.replace('l','m'));
        System.out.println(str);
    }

}
